Hmm. I tried 'Delete everything', deleted the app and removed the .whatsapp folder in /home/nemo/, reinstalled and registered but now I can't seem to sync any contacts. I can still see the groups that I belong to but I'm not able to add contacts one by one or sync the entire phonebook. Did I mess something up? And when I try to send a message with my other phone, it only arrives after I disconnect and reconnect. And when I try to reply my message isn't delivered. So I guess the original problem wasn't fixed :/